Disease Law and Forecasting of the Needle Blight ofPinus sylvestris var. mongolica

IntroductionNeedleblightofPinussylvcsIrisvarmongolicaisoneofthemaindiseaseonPinus3:VlvesIrlAvar.mongolicawhichisanativesPeciesinthearcabetWecnHulunbcirgrasslandandforest.Thisdiscaseisnotcdforscriousinfestation,fastspreadanddifficulttobecontrolled.Inthepas…     

Blight of conifer seedlings caused by Colletotrichum gloeosporioides

In a growth chamber experiment, 70-day-old seedlings of 10 conifer species were inoculated with Colletotrichum gloeosporioides conidia to determine the host range of the fungus. Based on the percentage of seedlings affected and the disease severity on individual seedlings, the order of most to least susceptibility was: western hemlock (WH), mountain hemlock, western larch, Sitka spruce, Engelmann spruce, Douglas-fir (coastal form, then interior form), white spruce and ponderosa pine; lodgepole pine and western red cedar remained unaffected. Inoculation of WH needles showed that within 24 h C. gloeosporioides conidia germinate and appressoria (penetration structures) form. A growth chamber study demonstrated that the pathogen can infect WH at needle wetness periods as short as 15 min; number of needles affected was higher at 0.5 h, but did not increase further even when wetness was extended up to 8 h. The results are discussed in relation to blight management of greenhouse-grown conifer seedlings.Portion of a Bachelor of Science (Honors) thesis, Department of Biology, University of Victoria, Victoria, British Columbia.     

锥栗对栗疫病的抗性与苯丙氨酸解氨酶的关系

健康的锥栗(Castanea henryi)皮层中,苯丙氨酸解氨酶(PAL)比活力与抗感病性之间不相关.不同抗病性的锥栗品种接种栗疫菌(Cryphonectria parastttca)后,PAL比活力均上升,接种144 h后,PAL比活力抗病性强的品种比抗病性弱的品种高.接种前以及接种后的各个时间内,木质素含量都是抗病品种比感病品种高.绿原酸的含量与品种的抗病性之间不呈规律性的相关,从绿原酸对栗疫菌菌丝生长影响的测定结果可知,锥栗体内的绿原酸浓度不足以影响栗疫菌.可见,接种后的皮层PAL比活力以及接种前、后的皮层木质素含量可作为衡量锥栗抗病性强弱的指标.     

园林植物病虫害系统控制的几点思考

分析了园林植物病虫害系统控制的重要性,针对园林病虫害系统控制的特殊性,从园林健康方面,提出了园林植物病虫害系统控制需注意的几个主要问题:园林工作者要具有园林健康意识,注重园林植物病虫害系统控制的科学性和前瞻性;建立本地区的园林植物病虫害和天敌以及小环境的系统网络体系,重视园林植物病虫害系统控制的目标化;乡土树种的合理利用和优质苗木的选育;进一步探索园林健康及病虫害系统控制的论证。     

Integrated Control Technique of Poplar Diseases in China

IntroductionNowthereservedarea-ofartificialforestsis3.3333xlO7hm2inChina,whiletheareaofPoplaris6.6xlo6hm2.ltmakesChinabecomethelargestcountryinpossess-ingartificialforestsofPoplar.PoplarvarietiesandnumberincreasegraduallyWithartificialforestsofpopIarrapid…     

Immunisation of pigs with a major envelope protein sub-unit vaccine against porcine reproductive and respiratory syndrome virus (PRRSV) results in enhanced clinical disease following experimental challenge

Disease exacerbation was observed in pigs challenged with virulent porcine reproductive and respiratory syndrome virus (PRRSV) following immunisation with a recombinant GP5 sub-unit PRRSV vaccine (rGP5) produced in E. coli. Eighteen animals were divided into three experimental groups: group A were immunised twice IM with rGP5, 21 days apart; group B acted as positive controls (challenged but not immunised); and group C were negative controls. Pigs in groups A and B were challenged 21 days after the second immunisation of the group A animals. Following challenge, three pigs given rGP5 exhibited more severe clinical signs than the positive controls, including respiratory distress and progressive weight-loss. Although not statistically significant, the more severe disease exhibited by group A animals may suggest previous immunisation as a contributory factor. The mechanisms of these findings remain unclear and no association could be established between the severity of disease, non-neutralising antibody concentrations and tissue viral loads.     

优质抗病厚皮甜瓜新品种苏甜2号的选育

苏甜2号为中早熟厚皮甜瓜杂交种。全生育期95d左右,果实发育期约35d。植株长势较强,抗白粉病和蔓枯病,较耐低温,易坐果。果实短椭圆形,果皮白色、光滑无网纹;肉厚3.8～4.2cm,果肉浅绿色,肉质软嫩,具有浓香味,中心可溶性固形物14.7%～16.8%。耐贮运。单果质量1.0～2.0kg,667m2产量2000～2300kg。适于华东地区及气候相似地区保护地栽培。     

Predicting the severity of Dothistroma on Pinus radiata under current climate in New Zealand

Despite being a damaging foliar disease of Pinus species little research has characterised spatial variation in disease severity of Dothistroma needle blight at a macroscale. Using an extensive dataset describing Dothistroma needle blight severity (S_sev) on plantation grown Pinus radiata stands distributed widely across New Zealand the objectives of this research were to (i) develop a regression model describing S_sev, (ii) use this model to identify key drivers of S_sev, their functional form and relative importance, and (iii) develop spatial predictions of S_sev for New Zealand P. radiata under current climate. Using an independent validation dataset, the final model accounted for 72% of the variance in S_sev using four significant (P < 0.001) explanatory variables and an isotrophic exponential model to account for the spatial covariance in the data. S_sev was most sensitive to mean air temperature from November to April (T_Nov-Apr), followed by mean relative humidity from October to April (RH_Oct-Apr), mean total November rainfall (P_Nov), and then stand age (A). There was a quadratic correlation between A and S_sev with S_sev increasing to a maxima at 12 years before declining. S_sev exponentially increased to a threshold with increases in both P_Nov and RH_Oct-Apr. The relationship between S_sev and T_Nov-Apr was quadratic with S_sev increasing to a maximum at T_Nov-Apr of 15.5 °C before declining at higher values of T_Nov-Apr. Spatial predictions of S_sev varied widely throughout New Zealand. Values of S_sev were highest in moderately warm wet environments in the North Island, and on the west coast of the South Island. In contrast, relatively low values of S_sev were predicted in drier eastern and southern regions of New Zealand.     

Dynamic relationships between soil properties and foliar disease as affected by annual additions of organic amendment to a sandy-soil vegetable production system

Additions of organic amendments to agricultural soils can lead to improved soil quality and reduced severity of crop diseases. However, the relationship between disease severity and soil properties as affected by repeated additions of these amendments is poorly understood. The primary objectives of this study were to (i) resolve multivariate relationships between soil properties and foliar disease severity and (ii) identify soil properties that contribute to disease severity in an intensive irrigated vegetable production system receiving annual additions of fresh and composted paper mill residuals (PMR). Foliar diseases caused by Pseudomonas syringae pv. syringae on snap bean (bacterial brown spot) and P. s. pv. lachrymans on cucumber (angular leaf spot) are the focus of this report. The experiment consisted of a 3-year crop rotation of potato (1998 and 2001), snap bean (1999 and 2002), and cucumber (2000). Treatments included a non-amended fertilizer control and two rates of fresh PMR, PMR composted alone (PMRC), and PMR composted with bark (PMRB). Soil measures included total soil carbon (TC) and nitrogen (TN), particulate organic matter carbon (POMC) and nitrogen (POMN), volumetric soil moisture (VM) and in situ NO₃-N. Multiple regression (MR) and principal component analyses (PCA) were conducted to identify key soil properties that influenced the amount of disease. On average, the amount of TC in plots amended with PMR composts increased 77-178% from 1999 to 2002 compared to the non-amended soils. In 1999, a year in which compost additions reduced the amount of bacterial brown spot of bean, TC explained 42% of the total variation in disease severity in the best MR model. Midseason TN alone was inversely related to angular leaf spot incidence in 2000, while POMN explained 51% of the variation in the best MR model for that year. In 2002, a year in which PMRC-amended soils exacerbated brown spot symptoms, midseason quantities of TN explained 80% of the variation in disease severity. Unique to 2002, NO₃-N alone positively correlated with disease severity. Overall, the influence of soil carbon on disease severity was displaced by the increasing importance of TN and NO₃-N, indicating a transition from a C-dependent to an N-dependent system.     

European bat lyssaviruses: Distribution, prevalence and implications for conservation

Worldwide, there are more than 1100 species of the Order Chiroptera, 45 of which are present in Europe, and 16 in the UK. Bats are reservoirs of, or can be infected by, several viral diseases, including rabies virus strains (in the Lyssavirus genus). Within this genus are bat variants that have been recorded in Europe; European bat lyssavirus 1 (EBLV-1), European bat lyssavirus 2 (EBLV-2) and, four currently unclassified isolates. Since 1977, 783 cases of EBLVs (by isolation of viral RNA) have been recorded in Europe. EBLV-1 or EBLV-2 has been identified in 12 bat species, with over 95% of EBLV-1 infections identified in Eptesicus serotinus. EBLV-2 is associated with Myotis species (Myotis daubentonii and Myotis dasycneme). A programme of passive surveillance in the United Kingdom between 1987 and 2004 tested 4871 bats for lyssaviruses. Of these, four M. daubentonii (3.57% of submitted M. daubentonii) were positive for EBLV-2. Potential bias in the passive surveillance includes possible over-representation of synanthropic species and regional biases caused by varying bat submission numbers from different parts of the UK. In 2003, active surveillance in the UK began, and has detected an antibody prevalence level of 1-5% of EBLV-2 in M. daubentonii (n = 350), and one bat with antibodies to EBLV-1 in E. serotinus (n = 52). No cases of live lyssavirus infection or lyssavirus viral RNA have been detected through active surveillance. Further research and monitoring regarding prevalence, transmission, pathogenesis and immunity is required to ensure that integrated bat conservation continues throughout Europe, whilst enabling informed policy decision regarding both human and wildlife health issues.